Controlling piglet diarrhoea with a holistic approach

Piglet diarrhoea can be viewed as caused by one particular reason – and hence the cure can be found by removing this cause. It might also make sense to view the problem of piglet diarrhoea from above: why not make sure that everything around the pig is in top condition? In this article, views from the feed/nutrition side is discussed.

Worldwide, there is a growing acceptance that a reduction of the consumption of antibiotics for animal production is needed. At the same time, there are also increasing concerns about the use of therapeutic levels of zinc oxide, which is allowed in some EU countries. This calls for a new approach to piglet nutrition with increased focus on both nutritive and non-nutritive sides of feeding young animals, including focus on strengthening the immunological status of pigs. This is why research by the Danish agricultural cooperative society (DLG Group) aims at a discontinuation of preventative use of antibiotics, as well as limiting the need for curative medication.

Limiting diarrhoea at weaning

Antibiotics can be used to solve digestive disorders at weaning. Application sometimes is done not only on a curative basis, but also preventatively, mixed in water or feed. There is a trend and a will, however, to even further reduce or even to completely remove the use of preventatively used antibiotics. This is not something just for the European Union, but in fact a tendency that can be observed throughout the whole of Europe.

Zinc oxide (ZnO) in some cases is very helpful in controlling piglet intestinal health, but it also has negative side-effects. There could be interactions with other nutrients, such as phytase, other minerals or a change of palatability of other substances.

Traditionally, different strategies have been applied to avoid or limit diarrhoea at weaning. These include the use of low crude protein levels (and high inclusion of crystalline amino acids), organic acids, pre- and/or probiotics and essential oils. Because not all essential amino acids are available in crystalline form, there is a limit to how low it is possible to go on a protein level, without impairing piglet performance, and an optimisation between protein level and performance has to be performed on herd level.

Where organic and inorganic acids* can be said to be included in generally all feed for piglets for solving health issues and improving performance, there are some differences between continents when it comes to the remaining product types. In an industry survey, the needs of the industry from Asia, Europe and the American continents was unanimously described as 'controlling piglet diarrhoea' and 'being able to create antibiotic-free diets'.

Understanding mechanisms

Besides focusing on the technological effect of additives, it is also vital to understand the mechanisms that determine feeding behaviour and non-nutritive effects created by feed and feed additives. These non-nutritive effects are referred to by different terms. The word 'eubiotics' is used for any compound or product that works through modification of the microflora; the term 'epigenetics' address the fact, that certain substances have been shown to be able to up- or down-regulate specific gene expressions, supporting the digestive and immunological abilities of the piglets.

Recent work, carried out at the Swine Innovation Centre in Sterksel, the Netherlands, shows that even though palatable creep feed is offered pre-weaning, a large proportion of piglets have not started to take in feed when the time of weaning comes. Time from weaning to first feed intake was significantly higher for these 'non-eaters', which influenced post-weaning performance.

What follows is that if the right high quality feed is used in creep/prestarter and starter feed, experience shows that piglets are more robust, and can be fed in a more cost-beneficial way, using high levels of soybean meal in diets for piglets from 15-20 kg.

Offering feed solutions after weaning is still a matter of great precision and quality.

Gut development stage is important

Administering feed that is not adapted to the gut development stage of the pig, often will lead to a non-infectious inflammation and diarrhoea. Research indicates that this kind of physiological stress might not only reduce performance at the time of the inflammation, but also could lead to an increased susceptibility to stressors for the remaining lifetime of the pig, lowering the threshold of diarrhoea and impairing lifetime productivity potential.

To better understand the link between feed quality and performance, a meta-analysis of validated performance data from more than 200 Danish herds concluded that using premium feeds leads to better performance. It seems that the markets are changing; it is recognised that it pays off to invest in high quality feed for young animals, to achieve and optimise overall lifetime performance. This probably is due to the fact that avoiding intestinal diseases in the early stages of life can be linked to a better lifetime performance.

Optimising protein supply

As the intestine of the small and newly weaned piglet is designed for digesting and absorbing proteins from milk, protein sources can be classified as 'iso-milk' proteins, depending on the digestibility and impact of the gastro-intestinal tract (GIT). Soy-protein concentrates from fermentation of extraction processes, potato protein concentrates, blood plasma and pea protein concentrate are components that can be considered iso-milk proteins.

Amino acids have other properties other than solely being a building block for protein synthesis. Specific amino acids have very important functions in immune function (methionine), gut epithelium and mucosa function and renewal (threonine), and neurotransmitters (tryptophane). When feeds are developed, aimed at challenged pigs, these should be formulated with an amino acid profile that takes these properties into consideration.

Properties of minerals

For several years, the Vilofoss group has been gaining experience and documentation on the benefits of including specific trace mineral chelates into piglet feeds. Including trace mineral chelates at levels corresponding to the maximum legal level within the EU, can be part of the strategy of controlling intestinal health in the post-weaning period. Field trials have shown, that to a certain extent, the inclusion of the concept PigOmic, performance can be increased, and the impact for E. coli infections can be reduced. In countries where therapeutic use of zinc oxide is legal, PigOmic can be used in the most cost-beneficial way, succeeding the ZnO administration. Only adding PigOmic to the diets, not using prophylactic treatment or antibiotic growth promoter (AGP) levels, or ZnO have been shown to reduce the impact of both general E. coli and also type O149, which leads to oedema disease.

Zinc – an essential trace mineral

In the late 1980’s, several researchers (e.g. Anders Holm, 1988; Hanne Damgaard Poulsen, 1989) proposed to supplement piglet feed with high level of zinc from oxide to reduce the severity and frequency of diarrhoea occurrence just after weaning. Since then, many studies have confirmed the positive effect on diarrhoea and growth performance. The addition of ZnO must be realised immediately after weaning and for two weeks to optimise its effectiveness considering clinical and ecological parameters. A synthesis of scientific studies has shown an improvement of growth performance between 10 and 30% when piglet feed was supplemented with 1,500 to 3,000 mg/kg of zinc from ZnO.

To limit the emission of zinc to the environment, a limited use by prescription has been adopted in a number of European countries. This, however, can be a temporary permission in some cases, which at some point probably is likely to be discontinued.

Above 1,000 mg/kg, zinc can induce an iron and a copper deficiency and lead to anaemia if the feed is not well balanced on these two trace elements. On top of this, there is some evidence, that once the treatment with ZnO ends, the balance of the microflora changes dramatically in the following weeks. Using amino acid chelates of zinc has been shown to improve gut integrity and improve performance with only 10% of the therapeutic levels of ZnO.

With the decreasing possibilities of using traditional antimicrobials, improved knowledge on the health management, not only around, but also inside piglet intestines is essential to keep productivity at its best.

New promising research results

For some time, it has been considered, that piglet diets had to be quite nutrient-dense to fulfill the animal's daily nutrient requirements, as it was assumed that piglets, due to a small volume of the GIT, have a low feed intake capacity. Recent studies have shown interesting results in using specific fibre fractions as an alternative to antibiotics in the feed. The exact correlation between fibre, health and growth is still not fully understood, but some authors have demonstrated a reduction of the severity of diarrhoea after weaning with high fibre diets, whereas for others fibre could increase pig susceptibility to diarrhoea.

This could be explained by the fact that there is a large variety of fibre with very different characteristics (digestible or not) and that there is no real recommendation regarding use of fibres in piglet diets. Fermentable fibre improves gut health in piglets: increase short-chain fatty acids (SCFA), decrease pathogens despite effects on growth performance. Nevertheless, from a practical point of view, the inclusion of fermentable fibre could be an additional risk factor after weaning especially in poor sanitary conditions. On the other hand, inert fibre could help limit digestive disorders and improve growth performance at weaning, but further research has to be done to better describe the type of fibre for a better use in piglet feed.

Plasma

From a technical point of view, blood plasma is one of the best alternatives to antibiotics. The use of blood plasma in piglet feed increases feed intake that is fundamental just after weaning. Blood plasma is also the best source of protein because it is not only a protein for growth but also a functional protein (immunoglobulins), that improves immunity and hence piglet health status. Studies have shown an improvement of growth performance by 25% on average when compared to other highly digestible protein sources as milk and soy protein sources. According to some veterinary experts, blood plasma has an important potential for reducing the use of antibiotics in digestive disorders of the piglet, by decreasing diarrhoea and mortality. They recognise that blood plasma improves palatability of the feed, growth rate and piglet health.

The use of plasma does not present any risk from a sanitary point of view if good practices (good manufacturing practice) are respected. Experts advise minimal requirements for plasma manufacturing. The heat treatment must be controlled in terms of temperature and duration, treated product storage of at least seven days must be applied and hygiene measures must be respected to avoid recontamination. Additionally, the origin of pig blood is regulated in Europe.

Even though protein sources of animal origin traditionally have been used for feeding young animals, the feed business can be forced in some cases to find non-animal alternatives, as the fear for contamination-related health issues is rising.

Piglet feed programme

The Vilofoss piglet programme Primefeed utilises the latest knowledge in pre-and post-weaning nutrition, offering feed solutions for piglets from birth to when they transition to more soybean meal (SBM) based diets. The earliest diet that can be offered in a hygienic way is a milk product, that includes the benefits of supplemental milk, teaches the piglets to eat dry feed, thereby easing the adaptation to more vegetable-based feeds in the creep/prestarter/starter range.

The programme offers solutions for the high-health, high-performing piglet, that benefits from highly digestible nutrient dense diets, through diets designed for optimal growth in more challenged piglets, to diets for more robust piglets, where a more competitive pricing is required. This means that the programme offers a feeding solution for all piglet producers, at any required level, and it will be possible to find the most cost-beneficial solution for each herd.

* Blends used at weaning should be an optimised mix of organic and inorganic acids, and minimum at 1% inclusion level.